/**
 * Copyright (c) 2010, Daniel Bimschas and Dennis Pfisterer, Institute of Telematics, University of Luebeck
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * 	- Redistributions of source code must retain the above copyright notice, this list of conditions and the following
 * 	  disclaimer.
 * 	- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 * 	  following disclaimer in the documentation and/or other materials provided with the distribution.
 * 	- Neither the name of the University of Luebeck nor the names of its contributors may be used to endorse or promote
 * 	  products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package de.uniluebeck.itm.nettyprotocols.isense.iseraerial;

import de.uniluebeck.itm.nettyprotocols.util.NettyStringUtils;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;

public class ISerAerialOutgoingPacket {

	public static final short BROADCAST_ADDRESS_16_BIT = (short) 0xFFFF;

	private static final int SERAERIAL_HEADER_LENGTH = 4;

	private final ChannelBuffer buffer;

	public ISerAerialOutgoingPacket(short destination, byte options, ChannelBuffer payload) {

		ChannelBuffer headerBuffer = ChannelBuffers.buffer(SERAERIAL_HEADER_LENGTH);

		{// Set destination (bytes 0-1)
			headerBuffer.writeByte((byte) ((destination >> 8) & 0xFF));
			headerBuffer.writeByte((byte) (destination & 0xFF));
		}

		{// Set option field  (byte 2)
			headerBuffer.writeByte(options & 0xFF);
		}

		{// Set length field (length of the payload) -  (byte 3)
			int length = payload.readableBytes();
			headerBuffer.writeByte(0xFF & length);
		}

		buffer = ChannelBuffers.wrappedBuffer(headerBuffer, payload);
	}

	/**
	 * Returns the (unmodifiable) buffer that backs this packet
	 *
	 * @return the backing buffer
	 */
	public ChannelBuffer getBuffer() {
		return ChannelBuffers.unmodifiableBuffer(buffer);
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder();
		builder.append("ISerAerialOutgoingPacket [buffer=");
		builder.append(NettyStringUtils.toHexString(buffer));
		builder.append("]");
		return builder.toString();
	}

}
